Relays are used to control household and other appliances, and especially for control of higher power consumption appliances such as refrigerators which include electrical compressors and defrosting elements that must be switched on and off regularly to function properly. Such relays have heretofore required substantial current drain to ensure reliable contact closure and to maintain such contact closure through the operation cycle of the appliance elements, such as the compressor and defroster in a modern refrigerator. Conventional latching relays are not preferred due to high cost, high operating currents, and other limitations.
Adaptive control of appliances, including refrigerators, is known. However, when coupled with the drivers required to operate conventional relays, whether of the latching type or otherwise, such advanced appliance controllers have been difficult to manufacture at the highly competitive low costs required in the consumer appliance market. Such controls have largely been limited to higher-end, commercial appliances and top line consumer appliances.
Examples of adaptive control of appliances, especially refrigerators include U.S. Pat. Nos. 4,251,988, 4,395,887, 4,850,204, 5,295,361, 5,479,785, all assigned to Paragon Electric Company, Inc., (a subsidiary of Siebe plc, parent of Robertshaw Controls Company, owner of the present disclosure), 5,533,349 and 5,533,350, both assigned to Robertshaw Controls Company, and others.